This invention pertains generally to the generation of high voltage pulses, and more particularly to the generation of high voltage pulses at a high pulse repetition frequency such as would be useful in a pulsed radar system.
In some pulsed radar systems, voltage pulses are applied to a controlling element of a klystron or microwave power tube to produce the radar pulses to be transmitted. High voltage pulses must be used in order to produce sufficiently powerful transmitted radar pulses. In a typical pulsed radar system using a gridded tube the pulses applied to the controlling element might have peak-to-peak amplitudes of several hundred volts. Therefore, circuitry capable of generating high voltage pulses is required.
Typically, a low voltage pulse train having the pulse repetition frequency and duty cycle desired for the transmitted radar pulses is first generated. Relatively common digital logic may be used to generate the low voltage pulse train that is then converted t the requisite high voltage pulse train by a step-up transformer, or a combination of step-up transformers.
The use of one or more step-up transformers to generate high voltage pulses suffers from several limitations. First, transformers generally have fixed limited bandwidths such that a pulsed radar system using transformers to transmit radar pulses at one pulse repetition frequency could not be used to transmit radar pulses at a significantly different pulse repetition frequency. Secondly, transformers generally are duty cycle limited and do not pass signals with high duty cycles. In pulsed Doppler radar systems, high pulse repetition frequencies must be used to accurately track fast targets. The maximum duty cycle of the transformer limits the maximum pulse repetition frequency for a fixed pulsewidth and hence the maximum speed of a target which can be accurately tracked.